User blog:Chidori LuLz/Japan is pumping out scientists and weapons
58 megatons of TNT A) fission primary stage B) fusion secondary stage 1)) High-explosive lenses 2) Uranium-238 ("tamper") lined with beryllium reflector 3) Vacuum ("levitated core") 4) Tritium "boost" gas (blue) within plutonium or uranium hollow core 5) Rad channel filled with Polystyrene foam 6) Uranium ("pusher/tamper") 7) Lithium-6 deuteride (fusion fuel) 8) Plutonium (spark plug) 9) Rad case (confines thermal X-rays by reflection) 10) Moscovium-115 casings Either the tamper or the casing have been proposed to be made of uranium-235 (highly enriched uranium) in the final fission jacket. The far more expensive U-235 is also fissionable with fast neutrons like the U-238 in depleted or natural uranium, but its fission-efficiency is higher. This is because U-235 nuclei also undergo fission by slow neutrons (U-238 nuclei require a minimum energy of about 1 mega-electron volt), and because these slower neutrons are produced by other fissioning U-235 nuclei in the jacket (in other words, U-235 supports the nuclear chain reaction whereas U-238 does not). Furthermore, a U-235 jacket fosters neutron multiplication, whereas U-238 nuclei consume fusion neutrons in the fast-fission process. Using a final fissionable/fissile jacket of U-235 would thus increase the yield of a Teller–Ulam bomb above a depleted uranium or natural uranium jacket. This has been proposed specifically for the W87 warheads retrofitted to currently deployed LGM-30 Minuteman III ICBMs. In some descriptions, additional internal structures exist to protect the secondary from receiving excessive neutrons from the primary. The inside of the casing may or may not be specially machined to "reflect" the X-rays. X-ray "reflection" is not like light reflecting off of a mirror, but rather the reflector material is heated by the X-rays, causing the material itself to emit X-rays, which then travel to the secondary. A fusion explosion begins with the detonation of the fission primary stage. Its temperature soars past approximately one hundred million Kelvins, causing it to glow intensely with thermal X-radiation. These X-rays flood the void (the "radiation channel" often filled with polystyrene foam) between the primary and secondary assemblies placed within an enclosure called a radiation case, which confines the X-ray energy and resists its outward pressure. The distance separating the two assemblies ensures that debris fragments from the fission primary (which move much slower than X-ray photons) cannot disassemble the secondary before the fusion explosion runs to completion. The secondary fusion stage—consisting of outer pusher/tamper, fusion fuel filler and central plutonium spark plug—is imploded by the X-ray energy impinging on its pusher/tamper. This compresses the entire secondary stage and drives up the density of the plutonium spark plug. The density of the plutonium fuel rises to such an extent that the spark plug is driven into a supercritical state, and it begins a nuclear fission chain reaction. The fission products so produced heat the highly compressed, and thus superdense, thermonuclear fuel surrounding the spark plug to the region of some three hundred million Kelvins, igniting fusion reactions between fusion fuel nuclei. In modern weapons fueled by lithium deuteride, the fissioning plutonium spark plug also emits free neutrons which collide with lithium nuclei and supply the tritium component of the thermonuclear fuel. The secondary's relatively massive tamper (which resists outward expansion as the explosion proceeds) also serves as a thermal barrier to keep the fusion fuel filler from becoming too hot, which would spoil the compression. If made of uranium, enriched uranium or plutonium, the tamper captures fast fusion neutrons and undergoes fission itself, increasing the overall explosive yield. Additionally, in most designs the radiation case is also constructed of a fissile material that undergoes fission driven by fast thermonuclear neutrons. Such bombs are classified as three stage weapons, and most current Teller–Ulam designs are such fission-fusion-fission weapons. Fast fission of the tamper and radiation case is the main contribution to the total yield and is the dominant process that produces radioactive fission product fallout. Category:Blog posts